Perhaps you should try some spelling variations:
hoc doanh » hoa doanh, hoc danh, hoc dan
doanh hoa » doanh khoa, doanh hoan, danh hoa
hoc sach » hoc sinh, hoc cac, hoc anh
sach doi » sach hoi, sach moi, sach dao
nhan dan » phan dau, gian dan
nhan tai » hang tai, van tai, toan tai
doi dau » doan dau
cuu mot » cua mot, cuu mo, huu mot
mot hoc » mon hoc, mo hoc, mot goc
ma hoi » mai hoi, xa hoi, ma hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach doi dau, nghien cuu mot hoc doanh hoa hoc ma hoi va ((nhan dan) or (nhan tai))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach doi dau, nghien cuu mot hoc doanh hoa hoc ma hoi va ((nhan dan) OR (nhan tai)).
• Adding a wildcard symbol may retrieve word variants: hoc sach doi dau, nghien cuu mot hoc doanh hoa hoc ma hoi va ((nhan dan) or (nhan tai))*.